International Journal of Environmental Science and Development, Vol. 5, No. 6, December 2014

Study of the Vulnerability of Coastal Areas of the Algerian Basin with the GIS

M. K. Mihoubi, R. Belkessa, and M. A. Latreche

 Transport sediments suspension concerns that ship without Abstract—The Bay of is of a strategic, economic, and being in contact with the bottom, and are lifted and moved in social, it is located in the heart of the Algerian capital, where the the water column due turbulent vertical velocities in the fluid. population density is high and many factories and commercial It is independent of transport by saltation, the particles in activities making it vulnerable to the pollution. Particularly suspension can traverse long distances at speeds of fall is along the coast, in addition to climate change, all this leads us to study their impact on the coast of Bay of Algiers, and exposure offset by upward fluid circulations. to risks of erosion and seawater intrusion. The aim of the work The transport by the sheet flow is located in the area near is the perception of vulnerable coastal areas by determining the the bottom, or the particles move in a disorganized way, coastal vulnerability index (CVI) at Bay of Algiers, based on when currents are intense and relatively coarse sediments. physical, geomorphological and hydrodynamic factors, coupled The flow sheet is a sedimentary layer that moves horizontally a study of groundwater vulnerability to risks bevel saline on the order of a few centimeters in height. This sediment particular endangered areas. These results obtained enable to project the future maps transport generates a accretion and erosion factors having an from the request processing on the state of the coastal system important role in hydro-sedimentary processes that using the Geographical Information System (GIS). Landmark contribute enormously in the evolution of the coastline at decisive tools to provide preventive and curative solutions to scales of a time and space very varied [3]. According to the coastal systems for better coastal protection particular to obliquity and direction of waves play an important role in estuarine areas, privileged place for exchange of sediment sediment transport at the shoreline by the orbital motion of transport. the waves [4]. The results of the study helped to locate areas of high vulnerability to moderate eastern bay of Algiers by the ICV Sediment transport can be done in a more complex way by index varying from 8 to 14. These values are still increasing in the currents induced by waves contributing to the movement the medium to long term if no Compensation by protective of the particles and the formation of the bars also known as structures unsupported consideration. sedimentary dunes including the transport direction is longitudinal or transversal [5] Regarding estuaries and river Index Terms—Bay of Algiers, coastal vulnerability, pollution, mouths, being the area of interaction of marine and river coast line, DRASTIC, CVI. waters seats exchanges of individual particles in suspension;

Thus shaping a morphological structure of estuarine landscapes. It is appropriate clear that the estuary differs from I. INTRODUCTION the mouth through the influence of the tide. According to the The coastline is a complex and sensitive environment, hydrodynamic parameters, count mouths dominated by actually, it combines two different areas, the land and sea fluvial inputs and those dominated by contributions from side, on either side affects the other over and above its role as waves [6]. They are also characterized by two movements of a living space, which is under pressure to order and water masses from the dynamics of waves and currents. anthropogenic climatic. These disruption and lead to numerous risks to the coastal system. Order to protect our environment, it is essential to seat an effective and II. METHODOLOGY sustainable approach to the management of coastal areas vulnerable. A. Coastal Vulnerability Index In the marine environment, flow of the water is responsible The importance of the coastline in the development of for sediment transport, where sediment particles can be tourism, industrial and petrochemical while ensuring transported in different ways. On this action, the morphology sustainable development in the coastal ecosystem makes us of the bottom will play an important role in the sediment more than ever to have decision support for integrated transport, thus causing sediment transport modes namely: management of the coastal system tools. Geographical According to the work [1], the bed load transport is the share information systems (GIS) can be a tool to help define the of total transport which the grains are always more or less in issues and future scenarios coastal processes. Taking into contact with the bottom during transport [2], the flow is slow account the sensitivity of the environment and the risks they or the particles are heavy. run, thus leading to highlight vulnerable areas. The physical vulnerability [7] of a coastal area expresses Manuscript received March 3, 2014; revised May 5, 2014. M. K. Mihoubi and M. A. Latreche are with Laboratory Mobilization and the degree and risk of physical changes that the middle can Recovery of Water Resource (LMVR-ENSH), National School for undergo. Hydraulics (ENSH), (e-mail: [email protected]). A title, such as floods, erosion and shoreline recedes, the R. Belkessa is with National School for Marine Sciences and Coastal Management (ENSSMAL). Algeria (e-mail: [email protected]). destabilization of coastal dunes, physico-chemical water

DOI: 10.7763/IJESD.2014.V5.538 522 International Journal of Environmental Science and Development, Vol. 5, No. 6, December 2014 degradation, silting of ports and coastal facilities. It expresses with the value of this index, and vulnerability to pollution is the degree to which a system is susceptible to, or be adversely higher for higher ribs. Several methods have been developed affected by the adverse effects of climate change, including indexed by DRASTIC principle which, for example: climate variability and extremes. Aquifer Vulnerability Index AVI method (Van Knowing that forecasting studies based on climate models Stempvoort et al, 1993) [10], developed in Canada considers: is agreeing in their majorities on important and negative (1) the depth and conductivity of each stratigraphic layers impacts of climate change by a magnitude of erosion and situated above the groundwater level and (2) the hydraulic decline of coastline over the next century. gradient. Analysis of the coastline is based upon a set tapes or C. Study Area segments. Each coastal segment will have a responsibility to respond unfavorably to a risk, the so-called vulnerability; it is 1) The database defined by the coastal vulnerability index (CVI) and defined Inventory data collection and consist of: files piezometers by Gornitz et al. 1994 [8], an empirical method widely used and drilling of the study area, files rates decline the shores of by United States Geological Survey (USGS). It is appropriate the Bay of Algiers, data relating to sea level rise in the remembered that this index can be used to identify areas Mediterranean and the amplitude of the tide. Other risqueet those most vulnerable to a rise in sea level from the cartographic data were analyzed such as: maps of wave simultaneous combination of six variables related to risk, heights at the hydrogeological and bathymetric Bay of according to the following relationship: Algiers, soil maps, geological, study areas. Other data were gathered during inventory have been 1 integrated from a digitization and conversion to part of the ICV (a*b*c*d*e* f ) (1) 6 system database. GIS is used MapInfo Professional 8.0, the software that we where, a: geomorphological variable, b: coastal slope, c: have more compatible implementation debase our data relative rate of rise of sea level, d: rate of decline of the system, and develop critical operations processed by three coastline, e: average tidal range, f: average wave height. cards software: timing, digitizing and thematic analysis Formulation and Gornitz et al., 1994 [8], closes six queries. variables because of their use in risk measurement for the Therefore it is possible analyzes a single variable (classes, coast. They are classified according to a linear scale of 1 to 5, individual values, dot density, proportional symbols) or and in an order of increasing vulnerability due to rising sea thematic multivariate analyzes (Fig. 1) level: a value of 1 would correspond to a very low risk and 5 as high There are four classes of risk are determined as follows: 1) Index low: low risk are less than 10. 2) Moderate Index: moderate risk range between 10 and 20. 3) High Index: high risk are between 20 and 30. 4) Index very high: very high risk are greater than 30. B. DRASTIC Vulnerability Index from an Aquifer Vulnérabilté DRASTIC index was developed in USA by the "National Water Well Association" (NWWA) in collaboration with "The U.S. Environmental Protection Agency" (EPA) [9]. It provides a model to assess the potential for contamination of aquifers independently of the type of pollutant and that takes into account most of the hydrogeologic factors that affect and control the flow of Fig. 1. Card Processing according to vulnerability through meaningful groundwater. colors. This index has the great advantage of being very easily integrated in a GIS. The acronym DRASTIC is derived from In our study area, to calculate the coastal vulnerability the initials of the seven physiographic and hydrogeological index, and apply the DRASTIC method, we made a mesh settings used in the model. The DRASTIC vulnerability along the coast of the Bay of Algiers, from the common Raїs index, given by the weighted sum for each parameter, each Hamidou (tip Pescade) to the town of El Marsa (Matifou) and partial index is derived by multiplying its coast by its relative at the surface of the vulnerable zone (the municipalities of: weight according to the following formulation sub-indices: , Mohammedia, , and). ID=(Dc.Dp)+(Rc.Rp)+(Ac.Ap)+(Sc.Sp)+(Tc.Tp)+(Ic.Ip)+(Cc.Cp) 2) The treatment (2) The treatment area consists of a square of 500 m side, each where: Dc: Coast parameter D; Dp: weight parameter D. cell has its data, and each has a given level of vulnerability, The DRASTIC index spreads over the whole range from the data type is a map (geographical, geological, 23 to 226, the risk of groundwater contamination increases hydrogeological...), a aerial photography, an Excel

523 International Journal of Environmental Science and Development, Vol. 5, No. 6, December 2014 spreadsheet, or a value directly attached. The establishment In this case, there was a gentle slope in the hollow of the of the final card is dealt to the superposition of tables, each bay which varies between 1 and 2.5%, but the minimum table represents a parameter responsibility to determine the value is the town of Bordj El Bahri (0.6%). The risk of erosion (down the coast), or pollution (contamination establishment of classes was performed on the basis of work of water) (Fig. 2). Thieler and Hammar-Klose (1999) [10] on the CVI (Fig. 4).

TABLE I: CLASSIFICATION OF THE COASTAL SLOPE FOR CVI (THIELER AND HAMMAR-KLOSE, 1999) Class of coastal vulnerability index(CVI) Very Low Moderate High Very High Low 1 2 3 4 5 Coastal >12 12-9 9-6 6-3 < 3 slope(%)

Fig. 4. Coastal Vulnerability according to the coastal slope of the bay of Algiers.

The rate climbed from sea to climate change and the increase in global temperature. Bay of Algiers located in the western part of the Mediterranean Sea, the rate of rise of sea level does not exceed the value of 1.1 mm / year , this value remains below 1, 8 mm / year where the CVI index is at its lowest value (Fig. Fig. 2. Mesh at the coastal area of Algiers. 5).

III. RESULTS AND DISCUSSION Morphological formation of the Bay of Algiers consists of three different types: From the town center Raїs Hamidou to Algiers, and the town of El Marsa Miocene and older rocks. The city of Belouizdad until Oued outlet: dune formations consolidated. The right bank of Oued El Harrach to the town of Bordj el Bahri (the plain of eastern Mitija) alluvium Mitija. Vulnerability almost very low at both ends of the bay, but the hollow of the bay of Algiers is very vulnerable, we also note that the risk factor is moderate along the shore of Bordj El Bordj El Bahri and Kiffan . Fig. 5. Coastal vulnerability according to sea level rise for the Bay of According to the morphological appearance of the Bay of Algiers.

Algiers (Fig. 3), the phenomenon of erosion threatens much Most of the shores of the Bay of Algiers is recorded a of the coastline, and it can lead to the loss of some beaches. moderate decline, except the sablettes beach, west of the

Algiers port has experienced accretion, we also note a high regression beaches of the town of Bordj El Kiffan, and at the town of Mohammedia east of the Bay of Algiers (Fig. 6).

Fig. 3. Coastal vulnerability morphology according to the Bay of Algiers.

Regarding the Bay coasts of Algiers, both ends of the bay have a generally higher slope with maximum values are 23% at the common Raїs Hamidou , ET19% in the Fig. 6. Coastal Vulnerability according to the evolution of the coastline for municipality of El Marsa. the Bay of Algiers.

524 International Journal of Environmental Science and Development, Vol. 5, No. 6, December 2014

As the tide in the Mediterranean basin is micro-tidal type because it at allow amplitude of the order of 0, 40 m, a very high value according CVI. Fig. 7 illustrates the vulnerability according to the average height of the waves on the Bay of Algiers.

Fig. 9. Percent of the coastline of Bay of Algiers for every degree of physical vulnerability.

The east and west of the Bay of Algiers regions are less affected because its morphological structure is rocky, and its slope generally higher, despite the intensity of the waves in these areas, but the vulnerability is almost moderate, except some shores experiencing low vulnerability (Raїs Hamidou, Fig. 7. Coastal Vulnerability according to the average wave height for the Bay of Algiers. El Marsa, and at the port of Algiers).

The combinations of all risk have identified the coastal vulnerability index in the form of Gornitz et al. (1994) [8]. IV. CONLUSION This index can detect the most sensitive areas and the factors To the coast of the Bay of Algiers, the most vulnerable responsible for risk. The values of this index we calculated areas are those with the lowest slopes, which mainly consist vary between 1.6 and 20.4 with an average value of 10.4, and of large sandy areas, and alluvial, especially the the median is 8.3. municipalities of: Hussein Dey, Mohammedia, Bordj el Using the method of lines quartiles (25%, 50%, 75%, Kiffan and Bordj el Bahri. The sea level rises by low speed 100%) and by visual inspection of the data, the results of the (not more than 1.1 mm / year), and the line of the coast ICV is divided into four categories, if the lower ICV 6 the regressed moderately along the coast, with a few exceptions. risk is low, and moderate between 6 from 1 to 8.3, and in the Regarding the hydrodynamic factors, there has been very range of 8.3 to 14 the risk is high if more than 14 risk they say high because the average amplitude of the tide (microtidal) is very high. On the map of coastal vulnerability, we gave risk, and a variation in intensity of the wave, since our area as each risk class a significant color (Fig. 8). a bay, and port facilities in the port of Algiers is an obstacle to the energy dissipation due to wave breaking. The Bay of Algiers, has a very high potential vulnerability, almost at the shores of Hussein Dey, Mohammedia, Bordj el Kiffan and Bordj el Bahri percentage about 30% along the coast, and almost 20% are areas of high vulnerability, moderate risk on 30 % of the coastline, and remaining 20% is a low risk outstanding at both ends of the Bay of Algiers in natural rocky areas.

REFERENCES [1] J. Fredsoe and R. Deigaard, “Mechanics of coastal sediment transport advanced series on ocean engineering,” World Scientific, Singapore, vol. 3, pp. 130-149, 1992. [2] V. Marieu, “Dynamics modeling of sediment ripples generated by waves,” PhD dissertation, Bordeaux I University, 2007. [3] R. L. Soulsby, Dynamics of Marine Sands, London: Thomas Telford Publication, ch. 8 and 9, pp. 129-166, 1997. Fig. 8. Coastal vulnerability index (CVI) for the coast of the bay of Algiers. [4] R. Bonnefille, Maritime Hydraulic Courses, 3rd ed. Masson, Ed. 1992, pp. 18-99. [5] B. Casstelle, “Modelling the hydrodynamic sediment over the sand It may be noted that the vulnerability at the shores of bars on subject to wave action: application to the Aquitaine coast,” PhD Hussein Dey, Mohammedia, and much of Bordj El Bordj El dissertation, Bordeaux I University, 2004. Bahri Kiffan and is very high, this is mainly due to the [6] L. D. Wright, “Sediment transport and deposition at river mouths: A synthesis,” Geology Society, Am. Bull., vol. 88, pp. 857-868, 1977. morphology of these areas. The structure of the beaches here [7] I. Mendizabal and P. J. Stuyfzand, “Quantify ing the vulnerability of is sandy and alluvial, where the slope is very weak, which weil fields towards anthropogenic pollution: The Netherlands as an makes the coast more vulnerable to soil erosion and flooding, example,” Journal of Hydrology, vol. 398, pp. 260-276, 2011. especially at the mouth of Oued El Harrach and Wadi El [8] V. M. Gornitz, R. C. Daniels, T. W. White, and K. R. Birdwell, “The development of a coastal risk assessment database: Vulnerability to Hamiz due to the lack of effective protection and sea-level rise in the U.S. southeast,” Journal of Coastal Research, vol. development (Fig. 9). 12, pp. 327-338, 1994.

525 International Journal of Environmental Science and Development, Vol. 5, No. 6, December 2014

[9] L. Aller, T. Bennett, J. H. Lehr, R J. Petty, and G. Hackett, “Drastic: A sediment transport coastal and measurement of the velocity profile in the standardized system for evaluating ground water pollution potential swash zone with Utrasonic Doppler Velocimetry (UDV). using hydrogeologie settings,” United States, Environmental protection Agency, June 1987. [10] E. R. Thieler and E. S. Hammar-Klose, “National assessment of coastal R. Belkessa was born in 1957. His is a professor at the vulnerability to sea-level rise,” Preliminary Results for the U.S. Superior National School of Marine Sciences and Atlantic Coast, U.S. Geological Survey Open-File Report, pp. 99-593, Coastal Management “Ecole Nationale Superieure des 1999. sciences de la Mer et de l’Aménagement du littoral" (ENSSMAL), Algiers. He has several research of the M. K. Mihoubi was born in 1996 in Algiers. In 1991, field of study of vulnerability. He is the director of a he was an engineer and a magister of engineering national research project on the prevention of natural water. He had the PhD degree in hydraulic at the disasters and protection against major risks Bay of National Polytechnic School of Algiers in 2008. He is Algiers. an assistant professor at the National School for Hydraulics "École Nationale Supérieure Author’s formal d’Hydraulique" (ENSH), Blida. He is the head of photo Hydraulic Engineering Departement. He is the author of numerous publications and contributions on

Author’s formal photo

526